nixos/homepage-dashboard: Allow multiple environmentFiles

Systemd supports passing a list to serviceConfig.EnvironmentFile to use
multiple environment files, this is useful to have a separate secret
file for each services listed on homepage, instead of one monolithic
file.

nixos/doc/manual/release-notes/rl-2605.section.md

@@ -97,6 +97,8 @@ of pulling the upstream container image from Docker Hub. If you want the old beh
 
 - `services.angrr` now uses TOML for configuration. Define policies with `services.angrr.settings` (generate TOML file) or point to a file using `services.angrr.configFile`. The legacy options `services.angrr.period`, `services.angrr.ownedOnly`, and `services.angrr.removeRoot` have been removed. See `man 5 angrr` and the description of `services.angrr.settings` options for examples and details.
 
+- `services.homepage-dashboard.environmentFile` has been renamed to `services.homepage-dashboard.environmentFiles`, and now expects a list of strings.
+
 - `services.pingvin-share` has been removed as the `pingvin-share.backend` package was broken and the project was archived upstream.
 
 ## Other Notable Changes {#sec-release-26.05-notable-changes}

nixos/modules/services/misc/homepage-dashboard.nix

@@ -10,6 +10,14 @@ let
   settingsFormat = pkgs.formats.yaml { };
 in
 {
+  imports = [
+    (lib.mkChangedOptionModule
+      [ "services" "homepage-dashboard" "environmentFile" ]
+      [ "services" "homepage-dashboard" "environmentFiles" ]
+      (config: [ config.services.homepage-dashboard.environmentFile ])
+    )
+  ];
+
   options = {
     services.homepage-dashboard = {
       enable = lib.mkEnableOption "Homepage Dashboard, a highly customizable application dashboard";
@@ -41,10 +49,10 @@ in
         '';
       };
 
-      environmentFile = lib.mkOption {
-        type = lib.types.str;
+      environmentFiles = lib.mkOption {
+        type = lib.types.listOf lib.types.path;
         description = ''
-          The path to an environment file that contains environment variables to pass
+          A list of paths to environment files that contain environment variables to pass
           to the homepage-dashboard service, for the purpose of passing secrets to
           the service.
 
@@ -52,7 +60,7 @@ in
 
           <https://gethomepage.dev/installation/docker/#using-environment-secrets>
         '';
-        default = "";
+        default = [ ];
       };
 
       customCSS = lib.mkOption {
@@ -243,7 +251,7 @@ in
 
       serviceConfig = {
         Type = "simple";
-        EnvironmentFile = lib.mkIf (cfg.environmentFile != null) cfg.environmentFile;
+        EnvironmentFile = cfg.environmentFiles;
         StateDirectory = "homepage-dashboard";
         CacheDirectory = "homepage-dashboard";
         ExecStart = lib.getExe cfg.package;